This guide will tell you how to achieve every 5 Endings for Nod's route, Yes especially the true ending which is the 5th one.
All 5 Endings
#1 A Sacrifice in Vain
This is by far the surprising and worst ending of all 5, It's a coincidence that it's also the first.
In this one you don't save Ollie's energy level What I mean is that all you do is to not bother talking to Ollie all the time by not asking for hints. (Hmph I'll let it slide this time but don't Neglect Ollie our Best girl and mascot next time).
Next you have to refuse Ollie's "Project" and choose the move on option where Nod tries to forget Irene and goes to the Hornet Aircraft then suddenly he see Mentor-15 standing on the ledge and nod tries to reach her to only get himself fall off 24 story down to earth with no Ollie to the rescue.
#2 Left Behind
In this one you may think the ending scene is the same but with a slight difference, Ollie uses her energy to save Nod from the fall how is that possible?
So in this one you have to save Ollie's energy and to do so you need to keep her busy from doing her little "Project" and more into talking and helping you, Whenever there is a yellow light bulb on Ollie's HUD icon that means Ollie has something to say and chat to you. The Dialogue from her is really great.
Looks like you don't know how or what to do in order to save Ollie's energy... Fortunately for you we have the full List of Ollie's Power consumption and energy saves!
#3 To Be With Her Again
In order to do this ending you can just go through the game casually it really doesn't matter what you do just get to chapter 7 and and accept Ollie's offer.
She will then transport you to "The world" for the 3rd and last time which once you in there you see a black door highlighted as Ollie's Promise and the Orange door. You can't really go through the orange door but to just observe it and the only option is to go through the black door where Nod sees.. Nod?
Yes Ollie takes over Nod's body and finally has freedom. Ollie then talk to Nod about how she was trying to tell him that she always wanted to get out be with him but Nod keeps mentioning Irene all the time on and on and on for the last 2 years that he didn't realise or hear what she has to say.
Ollie really did loved him... until now
#4 The Final Lesson
Hmm "The Irony" that we go back and do almost the same thing as Ending #2, Well let me tell you what is so different. You make Mentor-15 angry and kill Nod due to nod not rescuing Thea and left her to die and Ollie dies from using all of her energy to save Nod, now it was all in vein.
You have to kill Thea in anyway you have can which is cruel but you have to do it if you want to do this ending.
You will also have to save all of Ollie's energy again I will give you the list again.
To get more about four ending, follow this link.
#5 Good Intentions...
Ok.. this is a really heartbreaking ending and Ollie did everything to be with Nod even if it took her years from like since she was bought by Nod, Yes Ollie went out of her way to help make the schematics of the synthesizer with some... modifications.
It had features that would make Irene love Arthur and break up with Nod and after 2 years of break up and depression Nod found it, the reason why and he was furious.
Anyways here's how you do it, You have to save ALL of Ollie's energy all over again this time I think you know how to save it all. You then turn off Unter's Axis power with all that out of the way you have to just click on ollie's HUD Icon "TWICE and she tells you to listen to some music" after she said that all you do is go exit to menu and go to music, there will be a this glowing device on the right of the music list:
Once you click on it you will then go through the 5th and final ending Enjoy the cutscene and dialogue. I'll just post 2 more pics of the ending. This is a really cool ending and all these Spoiler images I have shown in this is not even covering 50% of it!